Stroke-changing mechanism for pneumatic tools.



\ PATENTED SEPT. s, 1903.

i. KELLER. STROKE CHANGING MEGEANISM EOE 'PNEUMATIG TooLs.

APPLICATION FILED DEO..8, 1902.

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No. 738.546. EATENTED SEPT. a, 1903. J. KELLER. STROKEGEANGING MEGHANISM EUR PNElrlvL/.nm TOOLS.

APPLIULTION FILEDV nEo. a, 1902.

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UNITED STATES Patented September 8,. 1903.

i PATENT OFFICE.

STROKE-CHANGING MECHANISM FOR PNEUIVITIC IDOLS.

SPECIFICATIONforming part of Letters Patent No. 738,546, dated September 8i, 19OS. Application filed December 8, 1902. Serial No. 134,273. (No model.)

without any change in the construction of the piston, distribution -valve, or coacting ports.

It is often very essential in various kinds of metal and stone work that in the beginning of the operation of the tool a long and powerful stroke is necessary, whereas in the Iinshing operation a lighter or shorter stroke is preferable. The old method of doing this work was to have one tool for the long stroke' for initial application to the Work and another tool with a short quick stroke for the finishing.' Y

The advantage of mynovel construction of stroke-changing mechanism whereby a single tool can be used at will to make a long or a short stroke will be evident to those skilledV in the art, since by my construction a single tool can be made to perform the work heretofore requiring two or more tools.

The invention further consists of the novel combination of a pneumatic tool-cylinder with a grasping-handle of either the pistolgrip or spade type, with a stroke-changing mechanism mounted on the cylinder of the tool.

It further consists of a novel construction of a pneumatic tool-cylinderhaving my novel stroke-changing mechanism applied thereto in combination with a grasping-handle applied to the tool and provided With a manually-operated throttle-valve for the purpose of controlling the initial admission of motive fluid to the tool.

It further consists of a novel construction of stroke-changing mechanism and means for locking the same in the desired position.

It further consists of novel details of con- `justing mechanism.

struction, all as will be hereinafter fully set forth, and pointed out inthe claims.

Figure l represents a longitudinal sectional view of a pneumatic tool having thereon a stroke-changing mechanism embodying my invention. Fig. 2 represents a longitudinal sectional View similar to Fig. l, but showing the piston and valve of the pneumatic tool in dierent positions. a longitudinal sectional view showing the pneumatic tool, valve, and piston substan= tially as seen in Fig. 2, but with the strokechanging mechanism in a different position. Fig. 4 represents a section on line Fig. 2. Fig. 5 represents a section on line yy, Fig. 3. Fig. 6 represents a perspective View of the hollow differential distribution-valve which I preferably employ. Fig. 7 represents a side elevation, partly in section, showing the application of my invention to a pneumatic tool having a long and short stroke adapted for metal work and having a grasping-handle of the spade type thereon. Fig. 8 represents a side elevation of a pneumatic hand-rammel' having my invention applied thereto and showing a plurality of handles thereon. Fig. 9 represents a side elevation of a pneumatic rammer having my invention applied thereto and provided with :a plurality of handles. Fig. 10 represents, on an enlarged scale, a perspective View of a portion of the stroke-ad- Fig. 1l represents a longitudinal sectional view of the cylinder seen in Figs. 1, 2, and 3, showing the preferred form of exhaust-passages therefor.

Similar numerals of 'reference indicate corresponding parts in the figures.

Referring to the drawings, l designates the cylinder of my novel tool, having the piston 2 therein, which is provided with the striker 3 and the groove 4t, said striker being movable within the ring 5, which is held in position in the end of said cylinder by the nosepiece 6, within which is contained the bushing 7.

8 designates the head block, which is screwed, clamped, or otherwise secured to the end of the cylinder and which holds in position the valve-box 9, within which is contained the distribution-valve 10. In the Fig. 3 represents IOO prefer to employ in practice the well-known Keller diierential valve, preferably constructed in accordance with the Keller patents, No. 647,415, granted April 10, 1900, and No. 647,416, granted April 10, 1900. In the present case the valve 10 has a passage 11 therethrough, a large differential area 12, a small differential area 13, on which live air constantly presses, a reduced neck 14, and an extension 15.

16 designates the live-air inlet, which leads the compressed air constantly into the passage 11 of the valve. p

,When the piston 2 is in the position seen in Fig. 2, the ports 17 and 18 are open, and the pressure on the large area 12 of the valve 10, which held the latter in the position seen in Fig. 1, will escape through the port 19,

`passages20 and 21, port 22, passage 23, port 18, and exhaust-port 17 into the atmosphere.

The pressure being now relieved from the large dierential area 12 of the valve, the latter will Vbe moved by the constant pressure on the small area13 from the position seen in Fig. 1 to the position seen in Figs. 2 and 3. The motive fluid can now pass through the passage 11 of the valve and through the ports 24 to drive the piston 2 forward or into the position seen in Fig. 1. In this position live air passes through the port 25, passage 26, and port 27, around groove 4, through port 28 and passages 21 20 and port 19, whereby the valve 10 is driven from the position seen in Figs. 2 and 3 by the pressure on the large area 12 into the position seen in Fig. l. The piston 2 and valve 10 being now in the position seen in Fig. l, live air can enter por 30, passage 3l, and port 32, thereby driving the piston 2 backwardly into the position seen in Fig. 2 again. The above-described operation will continue as long as the strokechanging mechanism 33 remains in the position seen in Figs. 1, 2, and 4, which indicate the shortest stroke of the piston 2. To make the piston-stroke longer, the stroke-changing mechanism 33 is turned, so that the springpressed latch or plunger 34, contained in the case 35, moves from its position in the seat 36, as seen in Fig. 4, into the position seen in Fig. 5, where it is locked in the seat 37, said plunger and case being carried by the ring 38,

which is rotatably mounted on the cylinder 1 and held between the shoulder 39 and the extremity of the nose-piece 6. As will be understood from Figs. 3 and 5, the connection between the ports 22 and 18 is now closed and out of service. fore on its backward stroke have to move to the position seen in Fig. 3 when exhaustport 40 is open, and the pressure which held the valve in the position seen in Fig. 1 will be released through port 19, passages 20 and 21 and port 41 into the exhaust-port 40, and as long as the stroke-changing mechanism is locked in the position seen in Figs. 3 and 5 the piston 2 will continue to make this long stroke, as is evident.

The piston 2 will thereand similar work which are manipulated by.

hand or mounted upon a crane or other suitable suppcrt, but also to pneumatic tools of every other description which are adapted to metal-work, as seen in Fig. 7, or to sandram mers manipulated by hand, as seen in Fig. 8, or to heavier sand-raminers adapted to be swung from a crane, as seen in Fig. 9.

In Fig. 7 I have shown apneumatic tool of the long-stroke type having the cylinder 42, provided with a grasping-handle 43, having the inlet-passage 44 for the compressed air which discharges through the port 45 into the valve mechanism, which I have not deemed it necessary to show and describe in detail, since the same may be of the character seen in Figs. 1, 2, 3, and 6 herein, conformingsubstantially to the fluid-distribution system seen in my prior patent, No. 647,415, herein'- before referred, or, if desired, I may employ the general construction of fluid-distribution system seen in my prior patents, Nos. 710,196 and 710,197, either with or without a stopvalve for starting the tool when the same is pressed to the work. The flow of compressed air through the duct or passage 44is controlled by the spring-actuated throttle-valve 46, contained in the bushing 47, said throttle-valve being operated by the pivoted lever 48, having the thumb-piece 49, adapted to underlie the workmans thumb or finger as he grasps the tool-handle 43. The coaction between the grasping handle and the stroke changing mechanism will be clearly apparent, since the operator can grasp the handle with one hand and with the other readily manipulate the stroke-changing mechanism to the desired extent.

l50 designates the ham mering-piston, which is preferably a plain cylindrical bolt whose stroke can be adjusted by the rotation of the ring 38, coacting with the passages 18, 22, and 23, whose function is the same as already eX- plained in connection with Figs. 1 to 5, inclusive.

51 designates the nose-piece of the cylinder 42, Within which is contained the shank of the working tool 52, which may be a buttonset when the tool is used for riveting or a chisel orotherchipping or tamping tool when the device is used for other kinds of work.

The ring 38 in Fig. 7 is locked in the desired position by the spring-pressed plunger `53, which engages the recess in said ring, this IOO IIO

of my invention as applicable to a pneumatic sand-rammer having the cylinder 53 having the grasping-handles 54 and 55 thereon, said cylinder containing the reciprocating piston 5o', to which the rod 57 is attached, having the stamper 58 thereon, said piston-rod and stamper reciprocating in unison. I have deemed it unnecessary to describe in detail the duid-distribution system seen in Fig.` 8, since it is of the same type as in my prior patent, No. 688,252, patented December 3, 1901. i

In Fig. 9 I have shown the broad principle of my invention as applied to a heavier type of sand-rammel' having the cylinder 59 and the reciprocating piston 60 therein, to which is attached the rod 6l, having the stamper62 thereon. I have deemed it unnecessary to describe in detail the fluid-distribution system seen in Fig. 9, since thesame is fully explained in my prior patent, No. 647,416, patented April l0, 1900. i

It will of course be apparent that my in- Vention is equally applicable to all other forms of pneumatic tools, irrespective of the use to which they may be put'or to the form ofgrasping-handles thereon. It will also be apparent that my invention is equally applicable to any construction ot piston, no matter whether the same is provided with a striker, as seen in Figs. l to 3, or is a plain cylindrical bolt grooved or ungrooved.

So far as I am aware, I am the first to equip a pneumatic tool of the character described with a stroke changing mechanism of the character explained, and my claims are therefore to be interpreted with corresponding scope.

It will be apparent that various changes may be made by those skilled in the art which,

may come within the scope of my invention, and I do not, therefore, desire tobelimited to the exact construction herein shown and described.

In Fig. 1l I have shown on a reduced scale the preferred arrangement of exhaust-passages for the piston seen in Figs. l, 2, and 3, but as the same are substantially similar to` my prior patent, No. 647,415, I have deemed it unnecessary to describe the same in detail.

I-Iaving thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

l. The combination of a pneumatic-tool cylinder, a reciprocating piston therein, and rotatable means concentric with said cylinder for varying the length of stroke of said pist0n.

2. The combination of a pneumatic-tool cylinder, a reciprocating piston therein, rotatable means concentric with said cylinder for varying the length of stroke of said piston, and devices for locking said means in either of its eXtreme positions.

3. The combination of a pneumatic-tool cylinder, a hammering-piston therein, a distribution-valve for said piston, and rotatable means concentric with said cylinder for lengthening or shortening the stroke of said piston.

4. The combination of a pneumatic -tool cylinder, a reciprocating piston therein, a differential distribution-valve for said piston, ports and passages intermediate said valve and piston, and a stroke-changing mechanism rotatable on said cylinder and concentric therewith and adapted in its extreme positions to permit a long or short stroke of said piston.

5. The combination of a pneumatic tool cylinder, a reciprocating piston therein, a distribution-valve for said piston, ports and passages intermediate said valve and piston, and a stroke-changing mechanism rotatable on said cylinder and concentric therewith and adapted in its eXtreme positions'to permit a long or short stroke ofsaid piston, and means for locking said stroke-changing mechanism in either of its extreme positions.

6. In a pneumatic tool, a cylinder; a piston therein, a Valve mechanism therefor, ports and passages intermediate said valve mechanism and said piston, and a stroke-changing mechanism for said piston consisting of a ring rotatably mounted on said cylinder. 7. In a pneumatic tool, a cylinder, a piston therein, a valve mechanism therefor, and a stroke-changing mechanism for said piston consisting of a ring having grooves therein rotatably mounted on said cylinder, in combination with means for locking said ring on either of its eXtreme positions.

8. In a pneumatic tool, a cylinder, a reciprocatingpiston therein, a distribution-valve 4for said piston arranged in alinement therewith,and means rotatable on said cylinder1 and concentric therewith for changing the length of stroke of said piston.

9. In a pneumatic tool, a cylinder, a reciprocating piston therein, a differential distribution valve for said piston arranged `in alinement therewith, and means rotatable on said cylinder and concentric therewith for adjusting the length of stroke of said piston.

l0. In a pneumatic tool, a cylinder, a reciprocating piston therein, a differential valve located eXteriorly to said cylinder, and means rotatable on said cylinder and concentric therewith for changing the length of stroke of said piston.

11. In a pneumatic tool, a cylinder, a reciprocating piston therein, means rotatable on said cylinder and concentric therewith for changing the length of stroke of said piston Without stopping the reeiprocation thereof, and a grasping-handle attached to said cylinder. i 12. In a pneumatic tool, a cylinder, a reciprocating piston therein, a grasping-handle attached to oneend of said cylinder, a strokechanging mechanism rotatable on said eylini der, and surrounding the latter and valve IOO IIO

mechanism intermediate said cylinder and handle.

13. In a pneumatic tool, a cylinder, a piston therein, a grasping-handle attached to one end of said cylinder, a valve mechanism held between said handle and cylinderand a stroke-changing mechanism mounted on said cylinder1 and consisting of a rotatable ring having grooves therein adapted to coact with ports in said cylinder.

14. In a pneumatic tool, a cylinder, a piston therein, a grasping-handle attached to one end of said cylinder, a valve mechanism held between said handle and cylinder and a stroke-changing mechanism mounted on said cylinder and consisting of a rotatable ring having grooves therein adapted to coact with ports in said cylinder in combination with means for locking said ring in either of its extreme positions.

15. In a pneumatic tool, a cylinder, a piston therein, a grasping-handle attached to one end of said cylinder, a valve mechanism held between said handle and cylinder and a stroke-changing mechanism mounted on said cylinder and consisting of a rotatable ring having grooves therein adapted to coact with ports in said cylinder in combination with a spring-pressed plunger common to said ring and cylinder for locking said ring in position.

16. In a pneumatic tool, a cylinder, areciprocating piston therein, a valve-block at one end of said cylinder, means for holding said valve-block in position, a valve mechanism in said valve-block, a grasping-handle for said cylinder, and a rotatable grooved ring mounted on said cylinder and adapted to connect and disconnect exhaust-ports in said cylinder.

17. The combination of a pneumatictoo cylinder having a grasping-handle thereon, a reciprocating piston in said cylinder and means rotatable on said cylinder and surrounding the latter for changing the length of stroke of said piston Without stopping the reciprocations thereof.

18. In a pneumatic tool, a cylinder, a grasping handle therefor, a manuallyoperated throttle-valve having therein means for controlling the initial admission of motive Huid to the tool, a reciprocating piston in said cylinder, and means rotatable on said cylinder and surrounding the latter for changing the length of stroke of said piston without stopping the reciprocations thereof.

19. In a pneumatic tool, a cylinder, a reciprocating piston therein, means surrounding said cylinder for varying the length of stroke of said piston, and engaging devices for locking said means in either of its extreme positions.

20. In a pneumatic tool, a cylinder, a reciprocating piston therein, means rotatable on said cylinder and concentric therewith for changingthe length of stroke of said piston, and a grasping-handle attached to said cylinder.

21. In a pneumatic tool, a cylinder having ports and passages therein and a ring rotatably mounted on the cylinder for changing the length of the piston-stroke.

22. In a pneumatic tool, a cylinder having ports and passages therein and a grooved ring rotatably mounted on the cylinder for changing the length of the piston-stroke.

23. In a pneumatic tool, a cylinder having a plurality of exhaust-ports and means rotatable on said cylinder and surrounding the latter for changing the length of the pistonstroke by opening or closing one of said ports.

24. In a pneumatic tool, a cylinder having a plurality of exhaust-ports and a grooved ring rotatable on said cylinder for changing the length of the piston-stroke by opening or closing one of said ports.

25. In a pneumatic tool, a cylinder having a plurality of longitudinally-disposed exhaust-ports and means rotatable on said cylinder and concentric therewith for changing the length of the piston-stroke by opening or closing one of said ports.

26. In a pneumatic tool, a cylinder having a plurality of longitudinallydisposed exhaust-ports and a' grooved ring rotatable on said cylinder for changing the length of the piston-stroke by opening or closing one of said ports.

27. In a pneumatic tool, a cylinder having ports and passages therein a ring rotatably mounted on the cylinder for changing the' length of the piston-stroke and means for detachably engaging said ring with said cylinder-in a 'plurality of operative positions.

28. In a pneumatic tool, a cylinder, a grasping-handle for said cylinder a manually-operated throttle-valve in said handle for controlling the initial admission of motive iluid to the tool, and means rotatable on said cyl` inder and concentric therewith for changing the length of the piston-stroke.

29. In a pneumatic tool, a cylinder, a grasping handle therefor and a ring rotatably mounted on said cylinder for changing the length of the piston-stroke.

, JULIUS KELLER.

I/Vitnesses:

JOHN A. WIEDERSHEIM, E. HAYWARD FAIRBANKS.

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